1. Technical Field of the Invention
The present invention relates to a magnetic resonance imaging (MRI) apparatus, and more particularly to an MRI apparatus capable of performing a plurality of different imaging methods time-sequentially based on a scan plan.
2. Related Art
An MRI is an imaging method of exciting the atomic nucleus spin of a tissue of an object (examined person such as a patient) placed in an static magnetic field by radio frequency signals (RF pulses) having the Larmor frequency thereof and reconstructing image data from magnetic resonance signals (MR signals) generated by the excitation.
The MRI apparatus is an image diagnosis apparatus for generating the image data based on the MR signal detected from the inside of a living body and indispensable in the present image diagnosis field because it is possible to obtain a lot of diagnosis information including not only dissection diagnosis information but also biochemical information, function diagnosis information, and the like.
In the MRI apparatus, various diagnosis image data relating to the object are collected by a main imaging to collect the image data used for a diagnosis to which, an imaging method group ordinarily constituted by time-sequentially arranging a plurality of different imaging methods, is time-sequentially applied. Then, the object is diagnosed based on the collected diagnosis image data. In this case, a scan plan is set by selecting an imaging condition of each of the imaging methods and a performing order for performing the plurality of imaging methods constituting the imaging method group using locator image data previously collected by, for example, a pilot imaging performed to the object, and the main imaging is performed based on the scan plan to collect the image data for the diagnosis (for example, it is mentioned in “Japanese Patent Application Publication No. 2006-231040”).
When the scan plan is set, an imaging time necessary to perform each of the imaging methods is approximately determined by a time necessary to collect MR signals which use a predetermined pulse-sequence (data collection time) and a time necessary to an image reconstruction processing and an image processing performed to the thus obtained MR signals (data processing time). Then, prior to the MRI examination, when a doctor and an examination engineer (hereinafter, called operators) in charge of the object perform a plurality of imaging methods in parallel so that data processing periods do not overlap, they set the performing order in which an examination time necessary to perform a plurality of imaging methods time-sequentially is minimized as one of scan plans.
Incidentally, a receiving RF coil (receiving coil) disposed the MRI apparatus to detect MR signals is ordinarily composed of a plurality of coil elements (array coils) to obtain good receiving sensitivity. When the image data is generated by performing data processings such as the image reconstruction processing, the image processing, and the like to the MR signals detected by these coil elements, a high speed arithmetic operation processing unit disposed to an image data generating unit prevents an increase of a circuit scale by subjecting the MR signals of a plurality of channels obtained from the coil elements to parallel processing.
However, since a data processing time to the MR signals is also increased because recently a data amount is increased abruptly by arranging an array coil as multi-channel array coil, an imaging time in each of the imaging methods greatly depends on a data processing time in addition to a data collection time. Since the data processing time of the data obtained by each imaging method depends on whether or not the high speed arithmetic operation processing unit can perform parallel processing, how long parallel processing time the processing unit requires, and the like, it is difficult for the operators to accurately grasp the imaging time of each imaging method from the imaging condition set by the scan plan. Further, it is difficult to set a preferable performing order capable of minimizing the examination time required by the imaging method group constituted by the plurality of imaging methods.